toddk911

So not really a boost issue per se. More of an issue when transitioning from vac to positive pressure and clears up once pressure is built.

So what could be faulty or sticking, etc. when going from vac to positive pressure?

User 52121

Good question. If it were a spark issue like some other folks suggested, I would think that it would get worse as boost continued to rise. If it's happening right at the transition, my guesses would be along the lines of a vac leak in the vac line system somewhere. Push enough pressure through and it'll still pressurize the lines while leaking... or a funky MAP signal.

msalvatore

could it be a bad MAP? or MAP wires?

bw993

I smoke tested the vacuum system @ 20 PSI and could not find any leaks. I also checked the wires for the MAP connection with a volt meter from the MAP plug to the DME connector and they were good.

Is there a good way to check the MAP sensor? If I apply 5 PSI to the MAP what voltage should I expect?

Rogue_Ant

To check the MAP sensor:

(Psi + 14.53) / 8.94 = volts

So 5psi would be ~= 2.18 volts.

bw993

Josh,

Just tested my MAP sensor at 5 PSI and the reading was 2.12 volts, so I assume my MAP sensor is good.

I think the hesitation problem I am having is the same issue that others on this board have identified with the MAP error detection algorithm in the older version of M-Tune software, which I have. Looks like I will need the latest software to fix my hesitation problem.

Thanks...

Rogue_Ant

Yep, I agree. An updated chip is en route.

joker2cv

I have the same problem!
Mine is a completely stock Turbo S

toddk911

Josh, is there a way to check if we have the latest chip versions with all the new revisions and updates?

Paulyy

what type of weather you having while driving? is it cold? warm?

bw993

20-30 C

Ben951S

Fuel pressure gauge in the car is helpful...

bw993

I have a gauge, 044 pump and adjustable fpr

bw993

Josh,

Got the updated chip and hesitation problem seems solved. I will check it out on the track soon. Thanks for all the user support.

Rogue_Ant

Good to hear!
Let me know how it goes at the track!